Linq高級查詢與分頁查詢
阿新 • • 發佈:2017-06-03
lec end context orderby ice source contains sco 平均值
Linq高級查詢
以~開頭:
r=>r.Name.StartsWith("李");
以~結尾:
r=>r.Name.EndsWith("光");
包含(模糊查詢):
r=>r.Name.Contains("四");
數據總個數:
Con.Goods.Count();||Con.Users.ToList().count;
最大值:
Con.Goods.ToList().Max(r=>r.Price);
最小值:
Con.Goods.ToList().Min(r=>r.Price);
平均值:
Con.Goods.ToList().Average(r=>r.Price);
求和:
Con.Goods.ToList().Sum(r=>r.Price);
升序:
Con.Goods.ToList().OrderBy(r=>r.Price);
降序:
Con.Goods.ToList().OrderByDescending(r=>r.Price);
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組合查詢:
<div>姓名:<asp:TextBox ID="T1" runat="server"></asp:TextBox></div> <div> 性別:<asp:DropDownList ID="DropDownList1" runat="server"> <asp:ListItem Text="男和女" Value="Null"></asp:ListItem> <asp:ListItem Text="男" Value="True"></asp:ListItem> <asp:ListItem Text="女" Value="False"></asp:ListItem> </asp:DropDownList> </div> <div> 成績:<asp:DropDownList ID="DropDownList2" runat="server"> <asp:ListItem Text="不限" Value="Null"></asp:ListItem> <asp:ListItem Text="大於" Value=">"></asp:ListItem> <asp:ListItem Text="小於" Value="<"></asp:ListItem> </asp:DropDownList><asp:TextBox ID="T2" runat="server"></asp:TextBox> </div> <asp:Button ID="Button2" runat="server" Text="查詢" />
void Button2_Click(object sender, EventArgs e) { using (StudentsDataClassesDataContext con = new StudentsDataClassesDataContext()) { List<Stu> s = con.Stu.ToList(); if (T1.Text.Trim().Length > 0) { s = s.Where(r => r.Name.Contains(T1.Text.Trim())).ToList(); } if (DropDownList1.SelectedValue != "Null") { s = s.Where(r => r.Sex == Convert.ToBoolean(DropDownList1.SelectedValue)).ToList();} if (DropDownList2.SelectedValue != "Null") { if (DropDownList2.SelectedValue == ">") { s = s.Where(r => r.Score > Convert.ToInt32((T2.Text.Trim()))).ToList(); } else { s = s.Where(r => r.Score < Convert.ToInt32((T2.Text.Trim()))).ToList(); } } Repeater1.DataSource = s; Repeater1.DataBind(); } }
組合查詢+分頁查詢:
Linq高級查詢與分頁查詢